Dynamic response of concrete beams reinforced with GFRP and steel bars under impact loading

This study explores the dynamic response of concrete beams reinforced with hybrid glass fiberreinforced polymer (GFRP) and steel bars under impact loading. A detailed three-dimensional nonlinear finite element model of concrete beams is developed, considering the strain rate effects for concrete, GFRP and steel bars. The accuracy of the numerical model is validated against experimental results available in existing literature. Based on the simulation results, the impact responses of hybrid GFRP-steel RC beams are discussed and compared with steel-RC and GFRP-RC beams. The study results reveal that increasing the effective reinforcement ratio of hybrid GFRPsteel RC beams enhances impact performance, with values above 1% found to be crucial for mitigating severe damage and deflection. Hybrid GFRP-steel RC beams with an effective reinforcement ratio ranging from 1.04% to 1.30% demonstrated enhanced impact resistance compared to GFRP-RC and steel-RC beams. Additional parameters affecting the impact response of hybrid GFRP-steel RC beams, such as impact location, configuration of tensile longitudinal bars, impact velocity and drop weight inclination angle, are explored.